The present invention relates to telecommunication techniques. More particularly, the present invention provides a two or more channel PAM4 modulator driver for silicon photonics modulator based high-rate (100G or greater) optical data transmission, though other applications are possible.
Over the last few decades, the use of communication networks exploded. In the early days Internet, popular applications were limited to emails, bulletin board, and mostly informational and text-based web page surfing, and the amount of data transferred was usually relatively small. Today, Internet and mobile applications demand a huge amount of bandwidth for transferring photo, video, music, and other multimedia files. For example, a social network like Facebook processes more than 500 TB of data daily. With such high demands on data and data transfer, existing data communication systems need to be improved to address these needs.
Progress in computer technology (and the continuation of Moore's Law) is becoming increasingly dependent on faster data transfer between and within microchips. Optical interconnects may provide a way forward, and silicon photonics may prove particularly useful, once integrated on the standard silicon chips. 40-Gbit/s and then 100-Gbit/s data rates DWDM optical transmission over existing single-mode fiber is a target for the next generation of fiber-optic communication networks. Everything is okay up to 10 Gbits/s, but beyond that, distortion and dispersion take their toll. Many approaches are proposed on modulation methods for transmitting two or more bits per symbol so that higher communication rates can be achieved. Mach-Zehnder modulators (MZM) can handle the higher data rates but require a driver that is differential with a large output voltage swing.
In the past, there have been many types of light modulation drivers and associated modulation techniques. Unfortunately, they have been inadequate in driving two independent channels of impedance matched traveling wave modulator with multi-level signals based on two-level NRZ digital inputs received from a transmitter ASIC for various applications in silicon photonics based data transmission. Therefore, improved drivers with advanced features are desired.